Effect of co-culture with vascular endothelial cells on promoting growth and suppressing apoptosis of C6 glioma cells under hypoxic condition

Objective To investigate the effect of co-culture with vascular endothelial cells on growth and apoptosis of C6 glioma cells under hypoxic condition.Methods C6 glioma cells and human umbilical vein endothelial cells were co-cultured with Transwell devices in 24-well plates;hypoxic condition was simulated by CoC12.C6 cells were divided into 4 groups:C6 cells and vascular endothelial cells were co-cultured under hypoxia as experimental group,while groups of co-culture of C6 cells and vascular endothelial cells under normoxia,monoculture of C6 cells under hypoxia,and monoculture of C6 cells under normoxia were used as controls.Apoptosis of C6 cells was detected by Annexin-V-FITC/PI double fluorescence staining and cell cycle of C6 cells was detected by flow cytometer 24 h after culture; the number of C6 cells was counted for 6 days and each growth curve was drew,respectively.Results After 24 h co-culture,apoptosis rate of C6 cells in the experimental group was obviously lower than that in control groups (P＜0.05); apoptosis rate of C6 cells in the group of co-culture of C6 cells and vascular endothelial cells under normoxia was significantly lower than that in group ofmonoculture of C6 cells under normoxia (P＜0.05).As compared with that in the other groups,the percentage of G0/G1 phase cells in the experimental group decreased apparently,but that of S phase cells was increased significantly in the experimental group (P＜0.05); percentage of G0/G1 phase cells in the group of co-culture of C6 cells and vascular endothelial cells under normoxia was significantly lower than that in group ofmonoculture of C6 cells under normoxia,but that of S phase cells was significantly higher in group of co-culture of C6 cells and vascular endothelial cells under normoxia (P＜0.05).After 6 d co-culture,C6 cells of each group grew fast in the first two days,reaching a peak during the following two days; in addition,C6 cells in experimental group grew fastest among the four groups,and its peak cell count was also the highest.Conclusion Co-culture with vascular endothelial cells under hypoxia can not only prevent glioma cells from apoptosis but also promote its growth. Key words: Glioma; Endothelial cell; Co-culture technique; Cell hypoxia; Growth; Apoptosis